Commit 9b0971ca authored by Paolo Bonzini's avatar Paolo Bonzini
Browse files

KVM: SEV-ES: fix another issue with string I/O VMGEXITs 



If the guest requests string I/O from the hypervisor via VMGEXIT,
SW_EXITINFO2 will contain the REP count.  However, sev_es_string_io
was incorrectly treating it as the size of the GHCB buffer in
bytes.

This fixes the "outsw" test in the experimental SEV tests of
kvm-unit-tests.

Cc: stable@vger.kernel.org
Fixes: 7ed9abfe ("KVM: SVM: Support string IO operations for an SEV-ES guest")
Reported-by: default avatarMarc Orr <marcorr@google.com>
Tested-by: default avatarMarc Orr <marcorr@google.com>
Reviewed-by: default avatarMarc Orr <marcorr@google.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 0985dba8

arch/x86/kvm/svm/sev.c

+12 −3
Original line number Diff line number Diff line
@@ -2579,11 +2579,20 @@ int sev_handle_vmgexit(struct kvm_vcpu *vcpu) 


int sev_es_string_io(struct vcpu_svm *svm, int size, unsigned int port, int in)

{

	if (!setup_vmgexit_scratch(svm, in, svm->vmcb->control.exit_info_2))

	int count;

	int bytes;



	if (svm->vmcb->control.exit_info_2 > INT_MAX)

		return -EINVAL;



	count = svm->vmcb->control.exit_info_2;

	if (unlikely(check_mul_overflow(count, size, &bytes)))

		return -EINVAL;



	if (!setup_vmgexit_scratch(svm, in, bytes))

		return -EINVAL;



	return kvm_sev_es_string_io(&svm->vcpu, size, port,

				    svm->ghcb_sa, svm->ghcb_sa_len / size, in);

	return kvm_sev_es_string_io(&svm->vcpu, size, port, svm->ghcb_sa, count, in);

}



void sev_es_init_vmcb(struct vcpu_svm *svm)